Exchanged messages are treated in conventional email systems similar to regular mail. Increasingly email is no longer standalone, or simple one way communication. A given email is now often part of a large protracted “conversation”, an interrelated series of messages that, when viewed over time and in aggregate, more closely resembles an interactive discussion between people and groups.
Interrelated messages are displayed by various electronic mail applications in different ways (e.g. tree structure, color scheme, use of graphics, etc.). However, many of the messages in the interrelated series include duplicate content from previous replies, forwards, and the like. When reading a series of related messages, the duplicate content tends to distract the reader and make it difficult to follow the flow of the exchange.
Because different electronic mail systems process messages differently and because unique content is not always uniformly inserted into the messages (e.g. inline comments, at the beginning of a reply, at the end of a reply, etc.), the unique content may not be extracted easily. Approaches such as tagging unique content also fail when one electronic mail system does not recognize a tag inserted by another electronic mail system.